"""
Build a strign with the numbers from 0 to 100,
"0123456789101112..." NOT use **str** and **%**
"""

import math


def d2s(d):
    """数字转字符串"""
    if not d:
        return '0'
    dig = int(math.log10(d)) + 1
    res = ""
    for i in reversed(range(dig)):
        res += chr(d // (10 ** (dig - 1)) + ord('0'))
        d %= 10 ** (dig - 1)
        dig -= 1
    return res


def f5(d):
    return ''.join([d2s(i) for i in range(101)])


if __name__ == '__main__':
    print(f5(100))
